# _*_coding:utf-8_*_


import matplotlib.pyplot as plt
from matplotlib.colors import ListedColormap
import numpy as np
import pandas as pd
import Perceptron


def plot_decision_regions(X, y, classifier, resolution=0.02):
    # setup marker generator and color map
    markers = ('s', 'x', 'o', '^', 'v')

    colors = ('red', 'blue', 'lightgreen', 'gray', 'cyan')

    cmap = ListedColormap(colors[:len(np.unique(y))])
    print(len(np.unique(y)))
    print(np.unique(y))
    # plot the decision surface
    x1_min, x1_max = X[:, 0].min() - 1, X[:, 0].max() + 1
    x2_min, x2_max = X[:, 1].min() - 1, X[:, 1].max() + 1
    xx1, xx2 = np.meshgrid(np.arange(x1_min, x1_max, resolution), np.arange(x2_min, x2_max, resolution))
    Z = classifier.predict(np.array([xx1.ravel(), xx2.ravel()]).T)
    Z = Z.reshape(xx1.shape)
    plt.contourf(xx1, xx2, Z, alpha=0.4, cmap=cmap)
    plt.xlim(xx1.min(), xx1.max())
    plt.ylim(xx2.min(), xx2.max())


    # plot classsamples
    for idx, cl in enumerate(np.unique(y)):
        plt.scatter(x=X[y == cl, 0], y=X[y == cl, 1], alpha=0.8, c=cmap(idx), marker=markers[idx], label=cl)
    return



if __name__ == '__main__':
    df = pd.read_csv('https://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data', header=None)

    row_len = df.shape[0]
    col_len = df.shape[1]
    y = df.iloc[0:row_len, 4].values

    y = np.where(y == 'Iris-setosa', -1, 1)
    X = df.iloc[0:row_len, [0, 2]].values
    plt.scatter(X[:50, 0], X[:50, 1], color='red', marker='o', label='setosa')
    plt.scatter(X[50:row_len, 0], X[50:row_len, 1], color='blue', marker='x', label='versicolor')
    plt.xlabel('petal length')
    plt.ylabel('sepal length')
    plt.legend(loc='upper left')

    plt.show('fg1')


    ppn = Perceptron.Perceptron(eta=0.1, n_iter=10)
    ppn.fit(X, y)
    plt.plot(range(1, len(ppn.errors_) + 1), ppn.errors_, marker='o')
    plt.xlabel('Epochs')
    plt.ylabel('Number of misclassification')
    fg2 = plt.show('fg2')

    plot_decision_regions(X, y, classifier=ppn)
    plt.xlabel('sepal length [cm]')
    plt.ylabel('petal length [cm]')
    plt.legend(loc = 'upper left')
    plt.show()




